Photo ideas: cross-polarisation photography

Learn how to take cross-polarisation photos and you’ll never look at plastic in the same way again. All you need for this photo idea are 2 polarisers and a spoon…

No, we haven’t gone crazy and over-the-top with our Photoshop manipulation in a monstrous flashback to the 1970s. These psychedlic colours have been created using a technique called cross-polarisation and it’s where weird and geeky science starts to get fun. Cross-polarisation photography takes advantage of the unique effect that polarised light has on some plastics and you’ll be amazed at the pictures you can create with a little creativity. Follow this simple tutorial to find out how it’s done.

Cutlery, glasses, French curves, rulers and other stationery… You’ll be able to get loads at the supermarket for less that £3 each.

Camera settings and technique:

1. Assemble your plastic props

First you’ll need to go to the local supermarket or stationery shop and load up with lots of cheap plastic products. The best kind of plastic is injection-moulded clear plastic such as transparent cutlery, stationary and glasses – try anything, but if it’s the kind of plastic that shatters easily you’ll get great results, especially if you stress it a little by bending it to near breaking point before you start.

2. Taking the shots

The technique is relatively simple. You basically need to photograph your plastic subject between two polarising filters. One polarising filter needs to cover the light source – we’ve used a sheet of polarising film on a lightbox, which is ideal. If you don’t have this try placing a polarising filter over another light source such as an angle-poise lamp. At around £40 a sheet for the polarising film you might want to think about sharing the cost with a like-minded photographer. Cut it in half and you’ll still get roughly two A4 sheets which is more than enough. Mount the second circular polarising filter on the camera or hold it in front of the lens if it doesn’t exactly fit.

3. Camera settings

Turn the main lights off, switch the lightbox on and place the plastic objects on it, so they’re essentially between the two filters. You’ll be able to see the cross-polarised effects the moment you look through the viewfinder. Rotate the circular polarising filter on your camera and watch the intensity of the effect change. At certain points the background will go completely black which is great for creating striking results. Switch your DSLR to Manual mode, use the histogram to establish a good exposure – we used f/8 at 1/25sec so a tripod was essential to avoid camera shake – and shoot away.

4. Photoshop tweaks

Take pictures in your camera’s RAW setting and process your files in Adobe Camera Raw. You only need a few basic tweaks, such as boosting contrast and colour vibrancy, to make the cross-polarised image look even better. The psychedelic displays of spectral madness you see here have had virtually no post production manipulation whatsoever.

Top tip: no polarising film? Use your PC…

If you don’t have a sheet of polarising film, use your PC screen set to white (try using Photoshop for this). It’s actually polarised, and will behave like a polarised lightbox. Alternatively, gaffa tape a second filter to a desk lamp.